Organization of roaming partner realms into primary and secondary

ABSTRACT

Various exemplary embodiments relate to a method performed by a policy and charging rules node (PCRN) of communicating with a roaming partner. The method may include: defining a roaming partner profile including a network identifier and a primary realm; receiving a session establishment request at the PCRN; extracting a subscription identifier from the session establishment request; determining an active roaming partner by comparing the subscription identifier to the network identifier; and establishing an S9 session with the primary realm of the active roaming partner. Another method may include: defining a roaming partner profile including a primary realm and at least one secondary realm; receiving an S9 session establishment request; extracting an origin realm from the S9 session establishment request; determining an active roaming partner by comparing the origin realm to the primary realm and the secondary realms of the roaming partner profile; and responding to the S9 session establishment request.

TECHNICAL FIELD

Various exemplary embodiments disclosed herein relate generally totelecommunications networks.

BACKGROUND

A communications network of a network provider usually has a limitedgeographical range where it can provide communications services. Networksubscribers usually subscribe to a single network. When a networksubscriber is outside of the geographical range of the subscribednetwork, another network provider may provide network service to thesubscriber, who is then considered a roaming subscriber. Thesubscriber's home network and the visited network must negotiate inorder to provide network service to the subscriber and correctlyapportion the costs of the service.

In view of the foregoing, it would be desirable to provide a method forproviding network service to a roaming subscriber. In particular, itwould be desirable to provide a network node and method for negotiatingthe service for the roaming subscriber with the other network.

SUMMARY

In light of the present need for a method for providing network serviceto a roaming subscriber, a brief summary of various exemplaryembodiments is presented. Some simplifications and omissions may be madein the following summary, which is intended to highlight and introducesome aspects of the various exemplary embodiments, but not to limit thescope of the invention. Detailed descriptions of a preferred exemplaryembodiment adequate to allow those of ordinary skill in the art to makeand use the inventive concepts will follow in later sections.

Various exemplary embodiments relate to a method performed by a policyand charging rules node (PCRN) of communicating with a roaming partner.The method may include: defining a roaming partner profile including atleast one network identifier and a primary realm; receiving a sessionestablishment request at the PCRN; extracting a subscription identifierfrom the session establishment request; determining an active roamingpartner by comparing the subscription identifier to the at least onenetwork identifier of the roaming partner profile; and establishing anS9 session with the primary realm of the active roaming partner byforwarding the session establishment request to the roaming partner.

In various alternative embodiments, the roaming partner profile includesat least one secondary realm. The subscription identifier may include acombination of Mobile Country Code (MCC) and a Mobile Network Code (MNC)that corresponds to a secondary realm, wherein the primary realm isassociated with a different combination of MCC and MNC than thesubscription identifier and the secondary realm. The primary realm maybe the only publicly addressable realm of the roaming partner. Themethod may also include configuring a Diameter route for only theprimary realm of a roaming partner. The roaming partner may internallyroute Diameter messages to a secondary realm.

Various exemplary embodiments relate to a method performed by a policyand charging rules node (PCRN) of communicating with a roaming partner.The method may include: defining a roaming partner profile including aprimary realm and at least one secondary realm; receiving an S9 sessionestablishment request via an S9 interface; extracting an origin realmfrom the S9 session establishment request; determining an active roamingpartner by comparing the origin realm to the primary realm and the atleast one secondary realm of the roaming partner profile; and respondingto the S9 session establishment request based on the active roamingpartner.

In various alternative embodiments, the step of responding to the S9session establishment request may include sending a message to theorigin realm of the received S9 session establishment request. Invarious alternative embodiments, the step of responding to the S9session establishment request may include generating a PCC ruleproviding a roaming subscriber with access to a network. In variousalternative embodiments, the step of responding to the S9 sessionestablishment request may include denying the S9 session establishmentrequest if the origin realm does not correspond to a roaming partner.

Various exemplary embodiments may relate to the above described methodsencoded as instructions on a non-transitory machine-readable medium. Thenon-transitory machine-readable medium may include instructions that ifexecuted by a processor of a network node perform the above describedmethod.

It should be apparent that, in this manner, various exemplaryembodiments enable methods for providing network service to a roamingsubscriber. In particular, by organizing roaming partner realms intoprimary and secondary realms, the PCRN negotiate the service for theroaming subscriber with the network of a roaming partner.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand various exemplary embodiments, referenceis made to the accompanying drawings, wherein:

FIG. 1 illustrates an exemplary subscriber network;

FIG. 2 illustrates an exemplary subscriber network for providing roamingaccess to various data services;

FIG. 3 illustrates an exemplary interface between a visited policy andcharging rules node (PCRN) and a home PCRN;

FIG. 4 illustrates an exemplary PCRN for providing service to a roamingsubscriber as a visited PCRN;

FIG. 5 illustrates an exemplary data structure for storing a roamingpartner profile;

FIG. 6 illustrates a flowchart showing an exemplary method of managing aconnection for a roaming subscriber at a visited PCRN; and

FIG. 7 illustrates a flowchart showing an exemplary method of managing aconnection for a roaming subscriber at a home PCRN.

DETAILED DESCRIPTION

A roaming subscriber poses difficulties for a visited public land mobilenetwork (VPLMN) because the network operator has little informationabout the subscriber. The VPLMN must make policy decisions forprovisioning a session for the roaming subscriber based on the littleinformation it has. The 3GPP specifications direct a VPLMN tocommunicate with the subscriber's home public land mobile network(HPLMN) to obtain the PCC and/or QoS rules necessary to establish asession for the subscriber.

The 3GPP specifications suggest using network identification informationsuch as a Mobile Country Code (MCC) and Mobile Network Code (MNC) toderive the realm of the HPLMN. This approach suffers from severallimitations. First, a service provider, particularly large serviceproviders, may use multiple MNCs and even multiple MCCs. A serviceprovider with multiple MNC/MCC combinations may wish to designate asingle publicly addressable realm for processing all requests forroaming subscribers. This approach may simplify configuration andprovide less information to roaming partners, who may also becompetitors. Second, a derived realm may be incompatible with non-3GPPnodes and previous releases. For example, CDMA nodes may use an NAI thatcannot be used to derive a realm. Also, a partner PCRN implementedaccording to a previous 3GPP release may not recognize derived realms.Finally, service providers may desire flexible configuration and may notfollow the suggested approach.

Organizing roaming partner realms into primary and secondary realms atthe PCRN may allow a service provider to configure communicationsbetween partner devices. The PCRN may limit outgoing S9 requests to asingle primary destination realm for each roaming partner. The PCRN mayrecognize incoming S9 requests from any realm used by a roaming partner.A network operator may configure roaming partner profiles to associatedifferent network and subscription identifiers with a roaming partner.As a roaming partner changes network infrastructure, for example, bymerging with another service provider, a network operator may easilyupdate the roaming partner profile.

Referring now to the drawings, in which like numerals refer to likecomponents or steps, there are disclosed broad aspects of variousexemplary embodiments.

FIG. 1 illustrates an exemplary subscriber network 100 for providingvarious data services. Exemplary subscriber network 100 may betelecommunications network or other network for providing access tovarious services. In various embodiments, subscriber network 100 may bea public land mobile network (PLMN). Exemplary subscriber network 100may include user equipment 110, base station 120, evolved packet core(EPC) 130, packet data network 140, and application function (AF) 150.

User equipment 110 may be a device that communicates with packet datanetwork 140 for providing the end-user with a data service. Such dataservice may include, for example, voice communication, text messaging,multimedia streaming, and Internet access. More specifically, in variousexemplary embodiments, user equipment 110 is a personal or laptopcomputer, wireless email device, cell phone, tablet, television set-topbox, or any other device capable of communicating with other devices viaEPC 130.

Base station 120 may be a device that enables communication between userequipment 110 and EPC 130. For example, base station 120 may be a basetransceiver station such as an evolved nodeB (eNodeB) as defined by 3GPPstandards. Thus, base station 120 may be a device that communicates withuser equipment 110 via a first medium, such as radio waves, andcommunicates with EPC 130 via a second medium, such as Ethernet cable.Base station 120 may be in direct communication with EPC 130 or maycommunicate via a number of intermediate nodes (not shown). In variousembodiments, multiple base stations (not shown) may be present toprovide mobility to user equipment 110. Note that in various alternativeembodiments, user equipment 110 may communicate directly with EPC 130.In such embodiments, base station 120 may not be present.

Evolved packet core (EPC) 130 may be a device or network of devices thatprovides user equipment 110 with gateway access to packet data network140. EPC 130 may further charge a subscriber for use of provided dataservices and ensure that particular quality of experience (QoE)standards are met. Thus, EPC 130 may be implemented, at least in part,according to the 3GPP TS 29.212, 29.213, and 29.214 standards.Accordingly, EPC 130 may include a serving gateway (SGW) 132, a packetdata network gateway (PGW) 134, a policy and charging rules node (PCRN)136, and a subscription profile repository (SPR) 138.

Serving gateway (SGW) 132 may be a device that provides gateway accessto the EPC 130. SGW 132 may be one of the first devices within the EPC130 that receives packets sent by user equipment 110. Variousembodiments may also include a mobility management entity (MME) (notshown) that receives packets prior to SGW 132. SGW 132 may forward suchpackets toward PGW 134. SGW 132 may forward such packets toward PGW 134.SGW 132 may perform a number of functions such as, for example, managingmobility of user equipment 110 between multiple base stations (notshown) and enforcing particular quality of service (QoS) characteristicsfor each flow being served. In various implementations, such as thoseimplementing the Proxy Mobile IP standard, SGW 132 may include a BearerBinding and Event Reporting Function (BBERF). In various exemplaryembodiments, EPC 130 may include multiple SGWs (not shown) and each SGWmay communicate with multiple base stations (not shown).

Packet data network gateway (PGW) 134 may be a device that providesgateway access to packet data network 140. PGW 134 may be the finaldevice within the EPC 130 that receives packets sent by user equipment110 toward packet data network 140 via SGW 132. PGW 134 may include apolicy and charging enforcement function (PCEF) that enforces policy andcharging control (PCC) rules for each service data flow (SDF).Therefore, PGW 134 may be a policy and charging enforcement node (PCEN).PGW 134 may include a number of additional features such as, forexample, packet filtering, deep packet inspection, and subscribercharging support. PGW 134 may also be responsible for requestingresource allocation for unknown application services.

Policy and charging rules node (PCRN) 136 may be a device or group ofdevices that receives requests for application services, generates PCCrules, and provides PCC rules to the PGW 134 and/or other PCENs (notshown). PCRN 136 may be in communication with AF 150 via an Rxinterface. PCRN 136 may receive an application request in the form of anAuthentication and Authorization Request (AAR) 160 from AF 150. Uponreceipt of AAR 160, PCRN 136 may generate at least one new PCC rule forfulfilling the application request 160.

PCRN 136 may also be in communication with SGW 132 and PGW 134 via a Gxxand a Gx interface, respectively. PCRN 136 may receive an applicationrequest in the form of a credit control request (CCR) (not shown) fromSGW 132 or PGW 134. As with AAR 160, upon receipt of a CCR, PCRN maygenerate at least one new PCC rule for fulfilling the applicationrequest 170. In various embodiments, AAR 160 and the CCR may representtwo independent application requests to be processed separately, whilein other embodiments, AAR 160 and the CCR may carry informationregarding a single application request and PCRN 136 may create at leastone PCC rule based on the combination of AAR 160 and the CCR. In variousembodiments, PCRN 136 may be capable of handling both single-message andpaired-message application requests.

Upon creating a new PCC rule or upon request by the PGW 134, PCRN 136may provide a PCC rule to PGW 134 via the Gx interface. In variousembodiments, such as those implementing the PMIP standard for example,PCRN 136 may also generate QoS rules. Upon creating a new QoS rule orupon request by the SGW 132, PCRN 136 may provide a QoS rule to SGW 132via the Gxx interface.

Subscription profile repository (SPR) 138 may be a device that storesinformation related to subscribers to the subscriber network 100. Thus,SPR 138 may include a machine-readable storage medium such as read-onlymemory (ROM), random-access memory (RAM), magnetic disk storage media,optical storage media, flash-memory devices, and/or similar storagemedia. SPR 138 may be a component of PCRN 136 or may constitute anindependent node within EPC 130. Data stored by SPR 138 may include anidentifier of each subscriber and indications of subscriptioninformation for each subscriber such as bandwidth limits, chargingparameters, and subscriber priority.

Packet data network 140 may be any network for providing datacommunications between user equipment 110 and other devices connected topacket data network 140, such as AF 150. Packet data network 140 mayfurther provide, for example, phone and/or Internet service to varioususer devices in communication with packet data network 140.

Application function (AF) 150 may be a device that provides a knownapplication service to user equipment 110. Thus, AF 150 may be a serveror other device that provides, for example, a video streaming or voicecommunication service to user equipment 110. AF 150 may further be incommunication with the PCRN 136 of the EPC 130 via an Rx interface. WhenAF 150 is to begin providing known application service to user equipment110, AF 150 may generate an application request message, such as anauthentication and authorization request (AAR) 160 according to theDiameter protocol, to notify the PCRN 136 that resources should beallocated for the application service. This application request messagemay include information such as an identification of the subscriberusing the application service, an IP address of the subscriber, an APNfor an associated IP-CAN session, and/or an identification of theparticular service data flows that must be established in order toprovide the requested service. AF 150 may communicate such anapplication request to the PCRN 136 via the Rx interface.

FIG. 2 illustrates an exemplary subscriber network 200 for providingroaming access to various data services. Exemplary subscriber network200 may correspond to exemplary network 100. EPC 230 v may providevisited access to packet data network 240 for roaming UEs such as UE210, whereby traffic associated with UE 210 flows through SGW 232 v andPGW 234 v. In various embodiments, EPC 230 v and EPC 230 h may connectto the same packet data network 240 (as shown) or may connect to twoindependent networks (not shown). Alternatively or additionally, EPC 230v may provide home-routed access to packet data network 240 for roamingUEs such as UE 210, whereby traffic associated with UE 210 flows throughSGW 232 v and PGW 234 h. Accordingly, SGW 232 v may be in communicationwith PGW 234 h. Likewise, SGW 232 h may be in communication with PGW 234v, such that EPC 230 h may provide similar access to other roaming UEs(not shown) attached to base station 220 h.

UE 210 may be in communication with a base station 220 v but outside therange of base station 220 h. Base station 220 v, however, may notconnect to a home public land mobile network (HPLMN) for the UE 210.Instead, base station 220 v may belong to a visited public land mobilenetwork (VPLMN) of the UE 210 and, as such, may not have access tovarious data associated with the UE 210, a subscriber associatedtherewith, and/or other data useful or necessary in providingconnectivity to UE 210. For example, SPR 238 v may not includeinformation associated with UE 210; instead, such information may bestored in SPR 238 h. To enable the provision of service based onsubscriber information stored in SPR 238 h, PCRN 236 v may communicatewith PCRN 236 h via an S9 session.

In various embodiments, PCRN 236 v may forward requests associated withUE 210 to PCRN 236 h via an S9 session. PCRN 236 h may process thesemessages to, for example, generate PCC and/or QoS rules. PCRN 236 h maythen forward these rules to PCRN 236 v for installation on PGW 234 vand/or SGW 232 v. In the case of home-routed access, PCRN 236 h may alsoinstall PCC rules directly on PGW 234 h. In view of the cooperativenature of PCRNs 236 h, 236 v, these devices may be referred to as“partner devices” with respect to each other.

In various embodiments, each partner device may be capable of operatingas a home device and a visited device. For example, if another roamingUE (not shown) were attached to base station 220 h, PCRN 236 h may beadditionally capable of forwarding requests to PCRN 236 v and PCRN 236 vmay be capable of returning appropriate rules to PCRN 236 h forinstallation.

FIG. 3 illustrates an exemplary interface 310 between a visited PCRN 236v and a home PCRN 236 h. Interface 310 may be an S9 interface. Interface310 may be used for communicating session establishment requests,provisioned rules, and other information between a visited PCRN 236 vand a home PCRN 236 h of a subscriber. Interface 310 may use messagesaccording to the Diameter protocol as described in the 3GPP TS 129.215specification.

Interface 310 may include zero or more S9 sessions 320. An S9 session320 may correspond to a roaming subscriber or a roaming subscriber'suser equipment. PCRN 236 v may establish a new S9 session 320 with PCRN236 h whenever a roaming subscriber seeks to establish a connectionthrough EPC 230 v. PCRN 236 v or PCRN 236 h may terminate an S9 session320 whenever the roaming subscriber disconnects from EPC 230 v.

S9 session 320 may include zero or more S9 subsessions 330. An S9subsession may correspond to an IP-CAN session of a user equipment of aroaming subscriber. An S9 subsession may be created whenever PCRN 236 vreceives a new request for a session. Information may be passed betweenPCRN 236 v and PCRN 236 h at the subsession level for the correspondingIP-CAN session. Alternatively, information may be passed at the sessionlevel for any IP-CAN session of a subscriber. PCRN 236 v may monitor thenumber of S9 sessions and S9 subsessions for each PCRN 236 h and/or eachroaming partner.

FIG. 4 illustrates an exemplary visited PCRN 136 for providing serviceto a roaming subscriber. PCRN 136 may act as both a visited PCRN such asPCRN 236 v and as a home PCRN such as PCRN 236 h. PCRN 136 may includeGxx interface 405, Gx interface 410, Sp interface 215 message handler420, user interface 430, roaming partner profile storage 440, routinginformation storage 450, roaming manager 460, and S9 interface 470.

Gxx interface 405 may be an interface comprising hardware and/orexecutable instructions encoded on a machine-readable storage mediumconfigured to communicate with a SGW such as SGW 232 v. Suchcommunication may be implemented according to the 3GPP TS 29.212. Thus,Gxx interface 405 may receive requests for QoS rules and transmit QoSrules for installation. Gxx interface 405 may further receiveUE-originated application requests, session requests, and eventnotifications in the form of a credit control request (CCR).

Gx interface 410 may be an interface comprising hardware and/orexecutable instructions encoded on a machine-readable storage mediumconfigured to communicate with a PGW such as PGW 234 v. Suchcommunication may be implemented according to the 3GPP TS 29.212. Thus,Gx interface 410 may receive requests for PCC rules and transmit PCCrules for installation. Gx interface 410 may further receiveUE-originated application requests, session requests, and eventnotifications in the form of a CCR.

Sp interface 415 may be an interface comprising hardware and/orexecutable instructions encoded on a machine-readable storage mediumconfigured to communicate with an SPR such as SPR 138. Sp interface 415may query SPR 138 with a subscription identifier. Sp interface 415 mayreceive a subscriber record from SPR 138. In various exemplaryembodiments, Sp interface 415 may be a network interface and communicatewith a remote SPR. In various alternative embodiments, the SPR may be alocal database within PCRN 136, and Sp interface 415 may query the localdatabase.

Message handler 420 may include hardware and/or executable instructionsencoded on a machine-readable storage medium configured to process rulerequests sent and/or received via Gxx interface 405 and/or Gx interface410. For example, message handler 420 may receive a rule request fromPGW 234 v for a roaming subscriber. After PCRN 136 makes a policydecision, message handler 420 may construct and transmit a message overGxx interface 405 and/or Gx interface 410 to notify other nodes as tothe result of the policy decision. For example, if PCRN 136 creates anew PCC rule according to an applicable policy, message handler 420 mayconstruct a reauthorization request (RAR) message to push the new PCCrule to an appropriate PGW.

User interface 430 may include hardware and/or executable instructionsencoded on a machine-readable storage medium configured to provide anetwork operator with access to PCRN 136. User interface 430 may receiveinput from a network operator and may include hardware such as, forexample, a keyboard and/or mouse. User interface 430 may also displayinformation as output to the network operator and may include, forexample, a monitor. A network operator may access roaming partnerprofile storage 440 via user interface 430. User interface 430 mayprovide a network operator with various options for creating roamingpartner profiles. A network operator may also configure routinginformation storage 450 via user interface 430.

Roaming partner profile storage 440 may include any machine-readablemedium capable of storing roaming agreements for use by PCRN 136.Accordingly, roaming partner profile storage 440 may include amachine-readable storage medium such as read-only memory (ROM),random-access memory (RAM), magnetic disk storage media, optical storagemedia, flash-memory devices, and/or similar storage media. As will bedescribed in further detail below with respect to FIG. 5, roamingpartner profile storage 440 may store numerous roaming partner profiles.Roaming partner profile storage 440 may include a cache for storingroaming agreements that are used frequently.

Routing information storage 450 may include any machine-readable mediumcapable of storing routing information for use by PCRN 236 v.Accordingly, routing information storage 450 may include amachine-readable storage medium such as read-only memory (ROM),random-access memory (RAM), magnetic disk storage media, optical storagemedia, flash-memory devices, and/or similar storage media. Routinginformation storage 450 may include routing information for sendingmessages to various network nodes and other networks. For example,routing information storage may include a mapping of realms andapplications to peer nodes. In various alternative embodiments, routinginformation storage 450 may be part of roaming partner profile storage440.

Roaming manager 460 may include hardware and/or executable instructionsencoded on a machine-readable storage medium configured to processrequests for service for a roaming subscriber. When acting as a visitedPCRN, PCRN 136 may receive a request in the form of a CCR messagereceived via Gx interface 405 or Gxx interface 410. Roaming manager 460may determine whether the request is for a roaming subscriber whoseHPLMN has made a contractual roaming agreement with the VPLMN.Accordingly, roaming manager 460 may extract a subscription identifierfrom the request for service. Roaming manager 460 may compare theextracted subscription identifier with various network identifiersstored in the roaming partner profile storage 440. Roaming manager 460may use information stored in roaming partner profile storage 440 androuting information storage 450 to establish a communication sessionwith a home PCRN, such as PCRN 236 h, of the subscriber over S9interface 470. Roaming manager 460 may forward any information includedin the service request to the home PCRN via the S9 interface. A moredetailed description of an exemplary method including steps performed byroaming manager 460 will be provided below with respect to FIG. 6.

Roaming manager 460 may also process requests from a roaming partnerdevice when PCRN 136 acts as a home PCRN such as PCRN 236 h. PCRN 136may receive a request in the form of a CCR message from a visited PCRN236 v via S9 interface 470. Roaming manager 460 may determine whetherthe request is from a roaming partner who has made a contractual roamingagreement with the HPLMN. Accordingly, roaming manager 460 may extractan origin realm from the received message. Roaming manager 460 maycompare the origin realm with a set of realms in each roaming partnerprofile. If the origin realm matches a roaming partner profile, roamingmanager 460 may generate one or more PCC rules and respond to therequest. Roaming manager 460 may obtain a subscriber record via Spinterface 415 when generating the one or more PCC rules.

S9 interface 470 may be an interface comprising hardware and/orexecutable instructions encoded on a machine-readable storage mediumconfigured to communicate with another PCRN. When PCRN 136 acts as avisited PCRN, S9 interface 470 may be used to establish an S9 sessionwith a home PCRN such as PCRN 236 h. When PCRN 136 acts as a home PCRN,S9 interface 470 may receive an S9 session request from a visited PCRNsuch as PCRN 236 v. Such communication may be implemented according tothe 3GPP TS 29.215. Thus, S9 interface 470 may forward requests forPCC/QoS rules to a partner device and receive PCC/QoS rules from apartner device for installation in the VPLMN. S9 interface 470 mayinclude an S9 session for each roaming UE connected to the VPLMN. Thepartner devices may use the established S9 session for monitoring andupdating the subscriber's connection while the UE is attached to theVPLMN. As described above regarding FIG. 3, an S9 session may includemultiple S9 subsessions if a roaming subscriber UE uses more than oneIP-CAN session.

S9 interface 470 may also be used when PCRN 136 acts as a home PCRN suchas PCRN 236 h. S9 interface 470 may receive requests for PCC/QoS rulesfrom a partner device and send PCC/QoS rules to the partner device forinstallation in the VPLMN. S9 interface 470 may also include an S9session for each subscriber UE of the HPLMN connected to another VPLMN.

FIG. 5 illustrates an exemplary data structure 500 for storinginformation about an exemplary roaming partner profile 505. It should beapparent that data structure 500 may be implemented using a variety ofdata structures such as, for example, objects, arrays, linked lists, ortrees. Data structure 500 may be stored in roaming partner profilestorage 440 or another computer-readable storage medium accessible toPCRN 136.

Exemplary roaming partner profile 505 may be one possible roamingpartner profile used by PCRN 136. Roaming partner profile 505 may beconfigured by a network operator using user interface 430 or may beimported from a computer-readable storage medium or other source. Itshould be apparent that PCRN 136 may use multiple roaming partnerprofiles. PCRN 136 may include one roaming partner profile for eachother service provider that has made a roaming agreement with theoperator of PCRN 136. Roaming partner profile 505 may include multiplefields including name 510, description 520, set of 3GPP Network IDs 530,set of domain names 540, set of realms 550, configuration information560.

Name 510 may indicate a unique name for the roaming partner profile.Name 510 may be used to identify the particular roaming partner. Name510 may be set by a network operator configuring the roaming partnerprofile. Exemplary roaming partner profile 505 may be named “Verizon” asindicated by name 510. Description 520 may include a textual descriptionof the roaming partner. Description 520 may provide a network operatoror other person viewing roaming partner profile 505 with an explanationof the roaming partner. For example, description 520 may indicate thatexemplary roaming partner profile 505 is for Verizon's US network.

The set of 3GPP Network IDs 530 may include a set of network IDs used bythe roaming partner. A 3GPP network ID may be part of an IMSI numberused to identify a subscriber. A 3GPP network ID may include a MobileCountry Code (MCC) 532 and a Mobile Network Code (MNC) 534. A roamingpartner may use multiple MCCs and multiple MNCs within the same country.The set of 3GPP Network IDs 530 may include entries 535. Each entry 535may include a MCC/MNC pair. Exemplary roaming partner profile 505 mayinclude three entries 535 a-c. Exemplary entry 535 a may indicate theroaming partner uses an MCC/MNC combination “310/004”. Exemplary entry535 b may indicate the roaming partner uses an MCC/MNC combination“310/005”. Exemplary entry 535 c may indicate the roaming partner usesan MCC/MNC combination “311/480”. Additional entries 535 may be includedfor other MCC/MNC combinations.

The set of domain names 540 may include a set of domain names used bythe roaming partner. A domain name may be used by a roaming partner aspart of a Network Access Identifier user to identify a subscriber. Theset of domain names 540 may include any domain name or variation ofspelling used by the roaming partner. Exemplary roaming partner profile505 may include two entries 545 a and 545 b. Exemplary entry 545 a mayindicate that the roaming partner uses “verizonwireless” as a domainname. Exemplary entry 545 b may indicate that the roaming partner uses“www.verizon.com” as a domain name. Additional entries 545 may beincluded for additional domain names and/or alternative spellings.

The set of realms 550 may include a set of realms used by the roamingpartner. The realm may provide an address to be used for communicatingwith the roaming partner. A realm may be a fully qualified domain name(FQDN) that unambiguously designates a Diameter realm of the roamingpartner. A realm may follow the naming convention described in 3GPP TS23.003. For example, a realm may be designated“gan.mnc123.mcc310.3gppnetwork.org.”

A realm may be a primary realm or a secondary realm. The primary realmmay indicate a Diameter realm that the roaming partner has indicatedshould receive all requests for roaming subscribers. Routing informationstorage 450 may include routing information for sending messages to theprimary realm. Each roaming partner profile 500 may include only asingle primary realm.

Secondary realms may indicate the realm of a PCRN that may act as avisited PCRN and send requests to PCRN 136 when it acts as a home PCRN.The roaming partner profile 500 may include a secondary realm for eachDiameter realm used to send messages from a roaming partner. If theroaming partner profile 500 does not include a primary realm or asecondary realm matching an origin realm of a received S9 request, PCRN136 may reject the request.

Exemplary set of realms 550 may include exemplary entries 555 a-c.Exemplary entry 555 a may indicate that the roaming partner uses“hprcn.verizon.net” as the primary realm for receiving requests forroaming sessions. Exemplary entry 555 b may indicate that the roamingpartner uses “pcrn2.verizon.net” as a secondary realm. Exemplary entry555 b may indicate that the roaming partner uses “pcrn3.verizon.net” asa secondary realm.

Configuration information 560 may indicate other useful informationabout the roaming partner. For example, release 562 may indicate aspecification version number that the roaming partner supports. Thisinformation may be used to ensure compatibility. As another example,vendor 564 may indicate a vendor of equipment such as the PCRN used bythe roaming provider.

FIG. 6 illustrates a flowchart showing an exemplary method 600 ofmanaging a connection for a roaming subscriber at PCRN acting as avisited PCRN. Method 600 may be performed by the various components ofPCRN 136 or PCRN 236 v including: message handler 420 and roamingmanager 460. Method 600 may begin at step 605 and proceed to step 610.

In step 610, PCRN 136 may provision one or more roaming partnerprofiles. A network operator may use user interface 430 to configure aroaming partner profile in roaming partner profile storage 450. Inparticular, the network operator may configure a primary realm for theroaming partner. The primary realm may be associated with a MCC and MNC.The network operator may choose a realm that the roaming partner hasindicated is publicly addressable for receiving S9 session requests. Theservice providers may have agreed which realms are publicly addressableas part of their contractual roaming agreement. The method may thenproceed to step 615, where the network operator may use user interface430 to configure Diameter routing information for the primary realm. Therouting information may include a peer node for determining a route forsending messages to the primary realm. The method may then proceed tostep 620.

In step 620 PCRN 136 may receive a session establishment request for aroaming subscriber via Gxx interface 405 or Gx interface 410. The methodmay then proceed to step 625, where PCRN 136 may extract a subscriptionidentifier from the received request. PCRN 136 may determine that thesession establishment request is for a roaming subscriber if thesubscription identifier indicates that the subscriber does not belong tothe home network of PCRN 136. The method may then proceed to step 630.

In step 630, PCRN 136 may determine to which roaming partner the roamingsubscriber belongs. PCRN 136 may compare the subscription identifier tothe various fields of roaming partner profile 500 to determine theroaming partner. For example, PCRN 136 may compare the first five or sixdigits of an IMSI number to the set of 3GPP network IDs 530. If thesubscriber ID is an NAI, PCRN 136 may compare the domain portion of theNAT to the set of domain names 540. If PCRN 136 is able to match thesubscription identifier to a network identifier of a roaming partnerprofile, the method 600 may proceed to step 640. If PCRN 136 is unableto find a matching roaming partner, PCRN 136 may deny the request toestablish a session in step 635.

In step 640, PCRN 136 may send a message to the roaming partner via theS9 interface. PCRN 136 may generate a CCR message requesting a new S9session for the roaming subscriber. PCRN 136 may set thedestination-realm field of the CCR to the primary realm of theidentified roaming partner. The primary realm may be different than arealm associated with an IMSI of the subscriber. For example, the IMSImay be associated with one of the secondary realms, but PCRN 136 mayestablish an S9 session with the primary realm. PCRN 136 may use theroute information storage 450 to determine a Diameter peer node to firstsend the CCR message. The method may then proceed to step 645.

In step 645 PCRN 136 may receive a response to the CCR message from apartner device within the primary realm of the roaming partner. PCRN 136may extract PCC/QoS rules from the received response and install therules in the VPLMN. Thus, PCRN 136 may provide service to the roamingsubscriber. The method may then proceed to step 650, where the methodends.

FIG. 7 illustrates a flowchart showing an exemplary method 700 ofmanaging a connection for a roaming subscriber at a home PCRN 236 h.Method 700 may be performed by the various components of PCRN 136 orPCRN 236 h including: message handler 420 and roaming manager 460.Method 700 may begin at step 705 and proceed to step 710.

In step 710, PCRN 136 may provision one or more roaming partnerprofiles. A network operator may use user interface 430 to configure aroaming partner profile in roaming partner profile storage 450. Inparticular, the network operator may configure a plurality of realms forthe roaming partner. The network operator may configure an entry in theset of realms 550 for each realm of the roaming partner that may requestan S9 session with PCRN 136. The service providers may have agreed whichrealms will be used as part of their contractual roaming agreement. Themethod 700 may then proceed to step 715,

In step 715, PCRN 136 may receive a CCR message requesting an S9 sessionfor a roaming subscriber. The CCR message may have originated at aroaming partner's visited PCRN. In step 720, PCRN 136 may extract anorigin realm from the CCR message. The origin realm may indicate therealm of the PCRN that sent the CCR message. In various alternativeembodiments, the origin realm may have been altered to a different realmof the roaming partner. The method may then proceed to step 725.

In step 725, PCRN 136 may determine whether the received CCR message isfrom a roaming partner. PCRN 136 may compare the origin realm to the setof realms 550 for each roaming partner. If the origin realm matches anyrealm of a roaming partner, either primary or secondary, PCRN 136 maydetermine that the message is from that roaming partner. If PCRN 136identifies a roaming partner, the method 700 may proceed to step 735. IfPCRN 136 is unable to identify the origin realm as belonging to aroaming partner, PCRN 136 may deny the session request in step 730.

In step 735, PCRN 136 may generate PCC/QoS rules for the roamingsubscriber. PCRN 136 may generate the PCC/QoS rules using informationfrom the CCR message, the roaming partner profile, and a subscriberrecord accessed via SP interface 420. PCRN 136 may consider the factthat the subscriber is roaming when generating the PCC/QoS rules. Themethod may then proceed to step 740.

In step 740, PCRN 136 may send the PCC/QoS rules to the origin realmthat requested the S9 session. PCRN 136 may send the PCC/QoS ruleswithin the established S9 session using the origin realm and pathinformation included in the CCR message. The PCC/QoS rules, if installedin the VPLMN, may provide the subscriber with the requested access tothe server and charge the subscriber appropriately. If the partnerdevice does not accept the PCC/QoS rules, PCRN 136 may receive a secondmessage within the S9 session. PCRN may then either send new PCC/QoSrules or deny the session request. The method may then proceed to step745, where the method ends.

According to the foregoing, various exemplary embodiments provide formethods for providing network service to a roaming subscriber. Inparticular, by organizing roaming partner realms into primary andsecondary realms, the PCRN negotiate the service for the roamingsubscriber with the network of a roaming partner.

It should be apparent from the foregoing description that variousexemplary embodiments of the invention may be implemented in hardwareand/or firmware. Furthermore, various exemplary embodiments may beimplemented as instructions stored on a machine-readable storage medium,which may be read and executed by at least one processor to perform theoperations described in detail herein. A machine-readable storage mediummay include any mechanism for storing information in a form readable bya machine, such as a personal or laptop computer, a server, or othercomputing device. Thus, a machine-readable storage medium may includeread-only memory (ROM), random-access memory (RAM), magnetic diskstorage media, optical storage media, flash-memory devices, and similarstorage media.

It should be appreciated by those skilled in the art that any blockdiagrams herein represent conceptual views of illustrative circuitryembodying the principals of the invention. Similarly, it will beappreciated that any flow charts, flow diagrams, state transitiondiagrams, pseudo code, and the like represent various processes whichmay be substantially represented in machine readable media and soexecuted by a computer or processor, whether or not such computer orprocessor is explicitly shown.

Although the various exemplary embodiments have been described in detailwith particular reference to certain exemplary aspects thereof, itshould be understood that the invention is capable of other embodimentsand its details are capable of modifications in various obviousrespects. As is readily apparent to those skilled in the art, variationsand modifications can be affected while remaining within the spirit andscope of the invention. Accordingly, the foregoing disclosure,description, and figures are for illustrative purposes only and do notin any way limit the invention, which is defined only by the claims.

What is claimed is:
 1. A method performed by a policy and charging rulesnode (PCRN) of communicating with a roaming partner, the methodcomprising: defining a roaming partner profile including: a networkidentifier, a primary realm indicating an address designated by theroaming partner to receive requests for roaming subscribers, and asecondary realm indicating a second address of the roaming partner;receiving a session establishment request at the PCRN from a roamingsubscriber; extracting a subscription identifier from the sessionestablishment request; determining an active roaming partner bycomparing the subscription identifier to the at least one networkidentifier of the roaming partner profile; and establishing an S9session with the primary realm of the active roaming partner byforwarding the session establishment request to the roaming partner. 2.The method of claim 1, wherein the subscription identifier includes acombination of Mobile Country Code (MCC) and a Mobile Network Code (MNC)that corresponds to a secondary realm, wherein the primary realm isassociated with a different combination of MCC and MNC than thesubscription identifier and the secondary realm.
 3. The method of claim1, wherein the primary realm is the only publicly addressable realm ofthe roaming partner.
 4. The method of claim 1, further comprisingconfiguring a Diameter route for only the primary realm of a roamingpartner.
 5. The method of claim 4, wherein the roaming partnerinternally routes Diameter messages to a secondary realm.
 6. A methodperformed by a policy and charging rules node (PCRN) of communicatingwith a roaming partner, the method comprising: defining a roamingpartner profile including: a primary realm indicating an addressdesignated by the roaming partner to receive requests for roamingsubscribers and at least one secondary realm; receiving an S9 sessionestablishment request from a roaming partner via an S9 interface;extracting an origin realm from the S9 session establishment request;determining the active roaming partner by comparing the origin realm tothe primary realm and the at least one secondary realm of the roamingpartner profile; and responding to the S9 session establishment requestbased on the active roaming partner.
 7. The method of claim 6, whereinthe step of responding to the S9 session establishment request comprisessending a message to the origin realm of the received S9 sessionestablishment request.
 8. The method of claim 6, wherein the step ofresponding to the S9 session establishment request comprises generatinga PCC rule providing a roaming subscriber with access to a network andsending the PCC rule to the roaming partner.
 9. The method of claim 6,wherein the step of responding to the S9 session establishment requestcomprises denying the S9 session establishment request if the originrealm does not correspond to a roaming partner.
 10. A tangible andnon-transitory machine-readable storage medium encoded with instructionsthereon for execution by a network element of a telecommunicationnetwork, wherein said tangible and non-transitory machine-readablestorage medium comprises: instructions for defining a roaming partnerprofile including: a network identifier, a primary realm indicating anaddress designated by the roaming partner to receive requests forroaming subscribers, and a secondary realm indicating a second addressof the roaming partner; instructions for receiving a sessionestablishment request at the PCRN; instructions for extracting asubscription identifier from the session establishment request;instructions for determining an active roaming partner by comparing thesubscription identifier to the at least one network identifier of theroaming partner profile; and instructions for establishing an S9 sessionwith the primary realm of the active roaming partner by forwarding thesession establishment request to the roaming partner.
 11. The tangibleand non-transitory machine-readable storage medium of claim 10, whereinthe subscription identifier includes a combination of Mobile CountryCode (MCC) and a Mobile Network Code (MNC) that corresponds to asecondary realm, wherein the primary realm is associated with adifferent combination of MCC and MNC than the subscription identifierand the secondary realm.
 12. The tangible and non-transitorymachine-readable storage medium of claim 10, wherein the primary realmis the only publicly addressable realm of the roaming partner.
 13. Thetangible and non-transitory machine-readable storage medium of claim 10,further comprising instructions for configuring a Diameter route foronly the primary realm of a roaming partner.
 14. The tangible andnon-transitory machine-readable storage medium of claim 13, wherein theroaming partner internally routes Diameter messages to a secondaryrealm.
 15. A tangible and non-transitory machine-readable storage mediumencoded with instructions thereon for execution by a network element ofa telecommunication network, wherein said tangible and non-transitorymachine-readable storage medium comprises: instructions for defining aroaming partner profile including a primary realm indicating an addressdesignated by the roaming partner to receive requests for roamingsubscribers and at least one secondary realm; instructions for receivingan S9 session establishment request via an S9 interface; instructionsfor extracting an origin realm from the S9 session establishmentrequest; instructions for determining an active roaming partner bycomparing the origin realm to the primary realm and the at least onesecondary realm of the roaming partner profile; and instructions forresponding to the S9 session establishment request based on the activeroaming partner.
 16. The tangible and non-transitory machine-readablestorage medium of claim 15, wherein the instructions for responding tothe S9 session establishment request comprise instructions for sending amessage to the origin realm of the received S9 session establishmentrequest.
 17. The tangible and non-transitory machine-readable storagemedium of claim 15, wherein the instructions for responding to the S9session establishment request comprise instructions for generating a PCCrule providing a roaming subscriber with access to a network.
 18. Thetangible and non-transitory machine-readable storage medium of claim 15,wherein the instructions for responding to the S9 session establishmentrequest comprise instructions for denying the S9 session establishmentrequest if the origin realm does not correspond to a roaming partner.